Electric motor telemetric system



J 1951 H. T. HOFFMAN EIAL 2,557,741

ELECTRIC IOTOR TELEIE'IRIC SYSTEI Filed Oct. 25, 1947 INVENTORS F 2 HOWARD T. HOFFMAN IG. MANTHQNY J.HORNFECK Patented June '19, 1951 I Z 557 741 2,557,741 ELECTRIC MOTOR TELEMETRIC SYSTEM Howard T. Hoffman, Cleveland, and Anthony J. Hornfeck, Lyndhurst, Ohio, lssignon to Bailey Meter Company, a corporation of Delaware Application October 25, 1947, Serial No. 782,112 3 Claims. (Cl. 318-18) the positions, of a transmitting member are into signals received from a transmitter. Other positioning an indicating member, and the motor In the accompanying drawing there is shown u s in h ease a pair f shadin pole for purposes or illustration two forms which our windings which are energized by a continuously l5 invention may assume in practice.

excited field. Rotation of the motor in opposite In this drawing:

directions is accomplished by short circuiting one F g. 1 is a schematic diagram of a telemetric or the other of the windings. One of the windsystem embodying our invention.

ings at the first receiver is connected to contacts Fig. 2 is a schematic diagram of a telemetric at the transmitter, and the other winding is consystem similar to that of Fig. 1 and embodying nected to contacts at the receiver. A closing of o r invention in another form.

the contacts at the transmitter and at the re- Referrin t the drawing, and more particuceiver short circuits the windings so that curlarly to Fig. 1, it will be noted that there is shown from the field winding. If the circuits to both of changes in some variable condition for transremains stationary while a short circuiting of The station I as shown herein, includes a one of the windings results in an operation of transmitting member 3 pivoted at 5 and operathe motor in one direct on o the other deDendtively connected to a device 6, such as a Bourdon ing upon which of the windings is short cir- 3 resistance of the circuit including the transliquid level, etc. Arranged at the receiver is a mitter contacts is so great that insuflicient combined receiving and indicating member 2 long distances, it is proposed that a relay be At the transmitting and receiving stations are in response similary shaped substantially uniform rise cams to the signals for controlling the short circuiting l2 a d M, respectively t t d i the dire tion of h D 1 W nding. It is also proposed that a of the arrows at a constant speed by motors l5, relaybe used in a phasing circuit for the motors I6 having windings I1 and I8 energized from a of the receiver motor is assured. scribed for holding the motor IS in phase rela- An object of our invention is to provide an imtionship with motor l5.

proved telemetric system. Another object is to Periodically reciprocated by the cams l2 and provide a telemetric system which permits the I are pivoted members 20 and 2| carrying conlocating of a receiver comparatively long distacts 22 and 23 respectively. Positioned by and to provide a system for transmittin signals member 24 carrying a contact 25 engageable by at low voltages over long lines and eflecting the contact 22. At the receiving station 2 is a 3 similar pivoted member 21 carrying a contact 28 engageable by the contact 23, and the member 21 is arranged to be positioned by the indicating member 9. When the cams l2 and H are rotated in exact phase the point on the contour of cam l2 engaged by the member 28 is the same as that on cam l4 engaged by the member 2|. If the position of the indicating member 9 corresponds with that of the transmitting member 3, the contact 23 will engage contact 28 at the same instant as contact 22 engages the contact 25. If, however, there is a change in the position of member 3, then the instant at which the contact 22 engages contact 25 will lead or lag the instant at which the contact 23 engages the contact 28 by an amount proportional to the change in the position of the member 3. The position of the indicating member 9 will then be corrected, as will be described, by an amount proportional to the change in position of the member 3, so that it is again in correspondence therewith.

The indicating member 9 is shown diagrammatically as being positioned by a reversible motor having opposed shading poles 3|, 32, and a field winding 33 continuously energized from a source of alternating current. Rotation of the motor in one direction is eifected by short circuiting the pole winding 3|, while rotation in the opposite direction is effected by short circuiting the winding 32. If the pole windings are both open circuited or both short circuited, the motor remains stationary and is not urged to rotation in either direction. For controlling the short circuiting of the pole winding 32 there is provided a relay 35 at the receiver having a winding 36 connected at one end directly to a source of direct current, and connectable at its other end through a conductor 31, the contacts 22, 25, and a conductor 38 to the source of direct current. A relay armature 48 is connected by a conductor 4| to one end of the pole winding 32 and carries a contact 42 engageable with a stationary contact 43 which is connectedby conductors 44, 45 and 46 to the other end of this pole winding. When the relay winding 36 is energized, the armature 48 is actuated to bring contact 42 into engagement with contact 43 and short circuit the pole winding 32. The pole winding 3| is connected at one end through the conductor 46 and the pivoted member 21 to the contact 28, and is connected at its other end through a conductor 41 and the pivoted member 2| to the contact 23. A short circuiting of the winding 3| is obtained on engagement between contacts 23, 28.

To provide for simultaneous deenergization of the pole windings there is provided in the common conductor 46 a mercury switch 48 positioned through a link 49 by the member 2 At a predetermined point in the travel of the member 2| the switch 48 is actuated to open the circuits through the pole windings 3| and 32. Upon return of the member 2| to another predetermined position, the switch 48 is closed so that the energizing of the pole windings may be controlled by the pairs of contacts 22, 2'5 and 23, 28. The switch 48 is arranged to close before the contacts 22, 25 or 23, 28 disengage regardless of the positions of the members 3 and 9, and to open while the contacts 22, 25 or 23, 28 are engaged regardless of the position of the members 3 and 9. In other words, energization of the pole windings 3|, 32 is controlled by contacts 23, 28 and 22, 25, respectively, whereas deenergization is controlled by the switch 48.

The operation of the system so far described is as follows: Assuming that the positions of the members 3 and 9 correspond with each other and that the cams |2 and H are rotating in phase at the same speed, the members 28 and 2| will be actuated to engage contacts 22, 23 with contacts 25, 28 at the same instant. Engagement'between contacts 22, 25 results in the energizing of the relay winding 36 to close contacts 42, 43 and short circuit the pole winding 32. Engagement between contacts 23, 28 results in a direct short circuiting of the pole winding 3|. With both pole windings short circuited at the same instant, the motor for the indicating member 9 remains stationary. If the condition changes so that the transmitting member 3 moves the contact 25 further from the contact 22, engagement between contacts 23, 28 will be obtained before there is an engagement between contacts 22, 25, and the short circuiting of the pole winding 3| will result in an operation of the indicator motor to move contact 28 away from contact 23. A change in the condition to move the contact 25 nearer to the contact 22 will result in an operation of the armature 48 to short circuit the pole winding 32 before the pole winding 3| is short circuited and efiect operation of the indicator motor to position the contact 28 nearer to contact 23.

The cams l2 and I4 may be out of phase when the system is first put into operation, or the cams may depart from the proper phase relationship during operation due to differences of friction in the motors. In order that they may be restored to proper phase relationship there is provided means whereby the angular position of the cam i4 is periodically compared with the position of the cam l2 and, if not in agreement, the motor I8 is momentarily stopped until the proper agreement is restored. To obtain correction in phase relationship there is provided on the pivoted member 24 a contact 58 which is engageable with a contact 5| carried by a pivoted member 52. Formed on the cam I2 is a projecting portion 54 which is adapted to lift the member 28 high enough to swing the member 24 so that its contact 58 engages the contact 5| once during each revolution of the cam. The member 52 is connected by a conductor 56 to one end of a winding 51 of the relay 35, and the other end of this relay winding is connected as shown to the source of D.-C. When the contact 58 engages the contact 5|, the relay winding 51 is energized from the D.-C. source through conductor 38, contacts 58, 5|, and conductor 56. A relay armature 59 carries a contact 68 engageable with a stationary contact 6| for completing a circuit from the A.-C. source through the motor winding i8, a conductor 62, the contacts 68, 6 l and a conductor 63 to the A.-C. source again. Another circuit is provided for the motor winding |8 through the conductor 62, a conductor 64, contacts 65, 68, a pivoted member 61, and the conductors 4'5, 63 to the source of alternating current. The contact 65 is supported in a fixed position, and the contact 66 is fixed to the pivoted member 61. A projecting portion 18 on the cam I4 is similar to the projecting portion 54 on the cam l2 and is operable to lift the pivoted member 2| sufliciently to swing the pivoted member 21 so as to engage the member 61 and effect a movement of contact 68 away from contact 65.

The contacts 65 and 66 are normally in engagement with each other so as to complete the circuit through the motor winding M for effecting operation of the motor to drive the cam N. If the cams l2 and H are in the proper phase relationship, the contact 66 is moved away from contact 55 at engages contact and energizes the relay wind- The circuit through the motor winding I 8 is then completed through the contacts 60, 6| as soon as it is broken at the contacts 65, 66, and the motor controlling the short ings 3| and 32 in response to signals produced as a result of opening and closing the contacts 22, 25 and 23, 28. The pole windings 3|, 32, are connected to the primary windings 14, of a step-up transformer 16, and the secondary windings 11, 18 of this transformer are connected at cathodes of the tubes 12, 13 while of the secondary windings are connected to the anodes of the tubes. A grid 80 of tube 12 is connected by a conductor 8| and the conductor 31 to the pivoted member 20, grid 82 of the tube 13 is connected by conductors 83, 84 to the pivoted member 2|. The pivoted members 24, 21 are connected respectively by conductors 38 and 85 to the negative side of the are connected by a conductor 86 to the positive side of the D.-C. source. When the contacts 22, 25 and 23, 28 are engaged, a negative potential is placed on the grids 80, 82 with respect to the cathodes and no current flows in the plate circuits of the tubes. When the contacts 22, 25 and 23, 28 are disengaged, the grids and cathodes are at the same potentials and current flows through the secondary windings 11, 18. The flow of current in the secondary windpole windings are short circuited and open circuited at the same time and the indicator motor If the transmitting member 3 and the indicating member 9 are in positions that do not correspond, the opening and closing of contacts 22, 25 either lead or lag the opening and closing of contacts 23, 28, and one or the other of the pole windings will be short circuited to effect operation of the indicator motor in a direction to bring the indicator into correspondence with the transmitting member 3. The motors l5 and I6 are held in phase in the same manner as described above in connection with the system of Fig. 1.

While there is described in this application two as new and desire to secure by United States Letters Patent is:

1. A telemetric system including in combination, a movable transmitting member, a movable energizing of said relay, and an A.-C. circuit including the pivoted relationship, said holding means including parallel A.-C. and D.-C. circuits for controlling the operation of the motor driving said receiver REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,046,676 Dueringer July 7, 1936 2,134,901 Wey Nov. 1, 1938 2,215,254 Ryder Sept. 17, 1940 2,231,569 Dickey Feb. 11, 1941 2,273,532 Lovell Feb. 17, 1942 

